1. Field of the Invention
The present invention relates to a vehicle door lock device.
2. Description of the Related Art
In recent years, a door lock actuator is used to switch a locking mechanism in a vehicle door lock device between a locked state and an unlocked state. In addition to the locking mechanism, a vehicle door lock device disclosed in Japanese Patent Application Laid-open No. 2001-20579 includes a child-lock mechanism for preventing a child from accidentally opening a door from inside the vehicle. The child-lock mechanism can be switched between a transmitting state and a non-transmitting state. The child-lock mechanism in the transmitting state transmits to a latching mechanism a signal regarding an attempt to open the door by using an inside door handle, while the child-lock mechanism in the non-transmitting state does not transmit the signal to the latching mechanism.
Meanwhile, in some of the conventional vehicle door lock devices, a key cylinder is not provided on the inside part of a door. As a result, the locking mechanism cannot be operated from inside the vehicle. Such a configuration enhances a security level of the vehicle against theft. That is, even if someone breaks a window of the vehicle, it becomes difficult to unlock the door from inside without the key cylinder.
However, in such a case, if the door lock actuator or a power supply system for the door lock actuator does not work properly due to a failure, it is difficult to unlock the locking mechanism if a key cylinder is not provided from inside the vehicle. Moreover, if the child-lock mechanism is switched to the non-transmitting state, then the latch of the door cannot be released. Thus, it is not possible to open the door from inside the vehicle when the door lock actuator does not work properly.